In the on-going battle over grant money for law enforcement, the U.S. Attorney General Jeff Sessions put Chicago on notice Thursday.

If it won't comply with federal regulations calling for police to assist immigration agents, the city could be at risk of losing out on federal dollars.

Speaking at an event in Roseland where he announced the opening of a new trade school, Chicago Mayor Rahm Emanuel made it clear Chicago will not be shutting down as a sanctuary city in the wake of the latest warning from the Department of Justice.

It came in letters sent to both Chicago Police Superintendent Eddie Johnson and Cook County Board President Toni Preckwinkle. In them, the DOJ said unless the city and county comply with federal regulations requiring police to cooperate with ICE agents, they could lose out on federal grant money to police.

City and county ordinances forbid police from assisting ICE in checking the immigration status of detainees.

"We are not going to be a city that picked between the philosophy of community policing and the principles of being a welcoming city," said Emanuel. "It is a wrong choice, a false choice and will get you nowhere."

"Whether it's an end to sanctuary city policies or an EEP verification system to ensure lawful employment only, they are supported by a vast number of Americans," said Sessions.

But Chicago's sanctuary city status wasn't the only target. Trump, speaking to Fox News Wednesday night, once again ripped Chicago over all the shootings and murders this year.

"It's really insulting to our nation. And whether you want to take on the NFL, or take on Chicago...there shouldn't be murders like this. And we have incredible police in this country. They could stop it, if they were allowed to do their job," Trump said.

"It is disconcerting - once again - to see how little President Donald Trump comprehends about policing in Chicago. He offers an "immediate" solution to gun violence - aggressive policing. We know what he means - this summer he told a room of graduating police officers to physically abuse suspects. Trump's Administration shirked its responsibility to address excessive force in Chicago after a damning report by Obamas Department of Justice. Now he calls for more abuse," the ACLU said.